Background: Studies on the effectiveness of community-based health interventions (CBHIs) in improving lifestyle practices among older adults are limited. Objectives: This study evaluated the impact of a CBHI on health knowledge, lifestyle goal attainment, and practices among older adults in Singapore. Methods: Older adults (aged ≥60 years) were recruited from 29 senior recreation centres to participate in the “Wise and Well” programme, a 3-month CBHI designed to empower individuals to make healthier lifestyle choices. Pre- and post-programme assessments of health knowledge, goal attainment, and lifestyle behaviours (dietary practices and physical activity levels) were conducted using a health knowledge questionnaire, Goal Attainment Scaling (GAS), the Modified Dietary Practice Questionnaire (DPQ), and the Global Physical Activity Questionnaire (GPAQ), respectively. Statistical analysis was performed using the Wilcoxon signed-rank and McNemar’s tests (α = 0.05). Results: The study comprised 464 participants (mean age 73.1 years [SD 7.6]; 75.9% women). Three months post-program, participants showed significantly increased health knowledge (p < 0.001) and improved lifestyle goal attainment (p < 0.001). Additionally, there was a significant increase in the proportion of participants meeting or exceeding fruit (p < 0.001) and vegetable (p = 0.002) intake recommendations and reductions in sugar-sweetened beverage consumption (p = 0.002). However, no significant changes were observed in fried food consumption or physical activity levels. High health knowledge scores were associated with 2.17 (95% confidence interval 1.02,4.64) times greater odds of increased vegetable intake. Conclusions: The CBHI shows potential as an effective approach to improving health knowledge and enhancing lifestyle goals and practices among older adults